Although in early spring the Slow-worm may be seen along hedgerows frequently in the daytime, later in the year it must be sought in the dusk when it is food-finding. It then spends the day under flat stones and in burrows. In Cornwall years ago we could always find a number of Slow-worms by turning over such loose stones along the top of the cliffs; and we have since found them pretty generally distributed without much regard to the nature of the soil. Its principal enemies--besides man--are the Viper and the Hedgehog. In the winter the Slow-worm retires--often in the company of half a dozen or so of its own kind--into an underground burrow or a hollow beneath a large stone, and goes to sleep; but it is the first of the reptiles to reappear at the very beginning of spring. Like its congeners it casts its skin from time to time--apparently about four times a year, but the frequency of the sloughing depends, of course, upon whether it is a good slug year or the reverse, for the shedding of the cuticle is in response to the demand for more room for the growing body. The Slow-worm's length of life is not known; but it does not appear to attain to sexual maturity until it is four or five years of age. We have reliable knowledge of one that was captured when about a foot in length (probably five or six years old), fifteen years ago, which is still healthy and active. [Illustration: _Pl. 90._ _K 144._ *Slow-worm.* Anguis fragilis.] [Illustration: _Pl. 91A._ *Grass Snake casts its skin.* 1. Immediately before sloughing.] [Illustration: _Pl. 91B._ *Grass Snake casts its skin.* 2. Operation nearly complete.] [Illustration: _Pl. 91C._ *Grass Snake casts its skin.* 3. In new attire.] [Illustration: _Pl. 92A._ *Head of grass snake.* A. Difference of form and scaling in heads of the two species.] [Illustration: _Pl. 92B._ *Viper.* B. Difference of form and scaling in heads of the two species.] [Illustration: _Pl. 93._ _L 145._ *Grass Snake.* Tropidonotus natrix.] It was in the Slow-worm that the discovery was made in 1886 of vestiges of a degenerate median eye connected with the pineal gland--a discovery that set all the biological investigators of the world at work. The same gland has in the last few years been found to have important influence in controlling the growth of the body in all vertebrates. The Slow-worm is generally distributed throughout the British Islands, with the exception of Ireland; it is much more plentiful in the south and south-west of England than in the east or north, but even in the south it is much more abundant in some districts than in others. Its wider range includes all but the extreme north of Europe, Western Asia, and Algeria. SNAKES *Grass Snake* (_Tropidonotus natrix_, Linn.).